Conservation group WWF has made a last-ditch effort to block a proposed liquefied natural gas (LNG) terminal in Hong Kong, slamming the government for approving an environmental study and saying the project could threaten rare pink dolphins.

A final decision is expected soon, following the government's approval of an environmental impact assessment for the proposed terminal, to be built by Hong Kong's largest power supplier, CLP Holdings Ltd.

But WWF says the LNG storage facility, to be built on the uninhabited Soko islands in Hong Kong's southern waters, would severely threaten the rich surrounding marine habitat, home to the highly endangered Chinese white dolphin and finless porpoise.

"If you keep pushing them (the dolphins) like this, at some point their numbers will start to go down," Andy Cornish, the director of conservation with WWF Hong Kong, told reporters.

"If they were capable of swimming somewhere else, I'm pretty sure they would have done it by now. They are evolved to live in this estuary," he added, referring to the Pearl River Delta estuary where they are found and nowhere else.

Only 80-140 of the endangered Chinese white dolphins remain in Hong Kong waters, and fewer than one thousand of the pink hued creatures survive in the whole of the Pearl River Delta.

The group accused the government of a narrow focus on energy security and said its approval of CLP's environmental impact assessment (EIA) report in April had sacrificed the environment as a necessary price.

"The EIA does no modelling to look at what will happen, it's basically just a subjective opinion, based on dubious assumptions ... we completely reject that," said Cornish.

In order to heat up the super-cold liquid LNG gas piped in by supertankers, the terminal would suck up huge volumes of sea-water, bearing small organisms like shrimp and fish larvae, resulting in the loss of 400,000 fish a year, WWF said.

"It's just going to create a dead zone around the out-take point," said Cornish.

But CLP rejected WWF's arguments.

"The proposed LNG terminal ... will not bring about significant negative impact to marine ecology or fisheries in the area," said the company in an e-mailed statement.

"The co-existence of a LNG terminal with a marine reserve is a well-tested arrangement. Seven terminals in the world co-exist with marine conservation," it added.

The government said in April that with a raft of mitigation measures in place as outlined in the EIA, it was "satisfied that the residual environmental impacts are acceptable and the relevant environmental requirements and standards can be met."

CLP's $1 billion facility, intended to serve as a joint venture power plant with Exxon Mobil Corp., will help the firm fulfil plans to use more clean gas to meet government-mandated emissions targets.

CLP has said it hopes to build a terminal to receive LNG gas by 2010 to help meet a target of slashing air pollutants by up to 20 percent from 1997.